compensation effect
In a considerable number of cases plots of TćS vs. ćH, for a series of reactions, e.g. for a reaction in a range of different solvents, are straight lines of approximately unit slope. Therefore, the terms ćH and TćS in the expression partially compensate, and \[\Delta ^{\ddagger}G = \Delta ^{\ddagger}H - T\ \Delta ^{\ddagger}S\] often is a much simpler function of solvent (or other) variation than ćH or TćS separately.
See also: isokinetic relationship
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1098 (